I have a P0106 error code on my 97 Subaru Legacy Outback. I just had a valve job done on the heads. I put the engine back together and put it back in the car, taking great care in the process. All hoses and wires were reconnected properly. The car runs fantastic. The only problem is the "check engine" light, P0106 error code. Would the pressure sensor go bad all of a sudden? Is there something I missed?
Cars & Trucks - Subaru - Outback
Answers & Comments
Using a scan tool, watch the MAP sensor value with the key on, engine off. Compare the BARO reading with the MAP reading. They should be roughly equal. The voltage for the MAP sensor should read approx. 4.5 volts. Now start the engine and look for a significant drop in the MAP sensor voltage indicating the MAP sensor is working.
If the MAP reading doesn't change perform the following:
With the Key on, engine off, disconnect the vacuum hose from the MAP sensor. Using a vacuum pump, pull 20 in. of vacuum on the MAP sensor. Does the voltage drop? It should. If it doesn't inspect the MAP sensor vacuum port and vacuum hose to manifold for a restriction of some kind. Repair or replace as necessary.
If there are no restrictions, and the value doesn't change with vacuum, then perform the following: with the Key on and engine off and the MAP sensor unplugged, check for 5 Volts at the reference wire to the MAP sensor connector with a Digital Voltmeter. If there is none, check for reference voltage at the PCM connector. If the reference voltage is present at the PCM connector but not the MAP connector, check for open or short in the reference wire between MAP and PCM and retest.
If reference voltage is present, then check for existing ground at the MAP sensor connector. If it isn't present then repair open/short in the ground circuit.
If ground is present, then replace MAP sensor.